Close-up on Fukushima pool debris

16 April 2012

Tepco has released images of debris including parts of a crane used for moving fuel in the used fuel pool at Fukushima Daiichi unit 3. Meanwhile, work is due to begin to cover unit 4's reactor building.

Underwater debris seen from the surface of the spent fuel pool (Image: Tepco)

A remote control underwater camera suspended from a crawler crane was lowered into the pool at the top of the unit 3 reactor building. The information provided by the survey will be used to inform actions to ultimately remove the debris from the pool, in accordance with Tepco's long-term roadmap for decommissioning the site.

Crane parts can be seen underwater in the pool (Image: Tepco)

When used fuel is removed from a nuclear reactor it is stored underwater for about three years before it can be transferred to dry storage facilities or sent for reprocessing. Used fuel pools are also used to store fresh fuel waiting to be loaded into the reactor. The pools at the Fukushima Daiichi reactors are located in the upper part of the reactor buildings.

Debris from the hydrogen explosion that demolished the upper part of the reactor building of unit 3 fell into the pond, and can be clearly seen in the images.

Tepco's roadmap foresees the removal of fuel from the pools, followed by the removal of debris, to be completed for all the spent fuel pools at the site within ten years.

Cover work begins

Work is about to begin on the installation of a cover over Fukushima Daiichi unit 4 prior to the removal of fuel from the reactor building, Tepco has announced. A cover has already been built over the remains of unit 1 and similar covers are due to be built over units 3 and 4. Preparatory work has been under way since late March and work will begin on the cover for unit 4 on 17 April, the company has announced.